A radioactive substance has a half-life of 1.25 million years. What is the age of a rock in which 6.25% of the original radioactive atoms remain? 5 million years old 6.25 million years old 3.75 million years old6 2.5 million years old 1.25 million years old 625 thousand years old
Answer:
The age of the rock is 5 million years
Explanation:
Fraction of radioactive substance remaining = 6.25% = 625/10000 = 1/16
Number of half-lives undergone by the substance to leave behind 1/16 of the original sample
1/16 = (1/2) * (1/2) * (1/2) *(1/2)
Therefore, the substance have decayed 4 times
One half=life = 1.25 million years
Four half-lives = 4 * 1.25 million years = 5 million years
Therefore, the age of the rock is 5 million years
If a person combat the disease without a vaccine introduced to his body,such immunity is known as
natural active immunity
natural passive immunity
Artificial active immunity
artificial passive immunity
Answer:
natural active immunity will be the answer
how does water boiling on a stove represent all 3 types of heat transfer
Answer:
For example, when a pot of water is placed on the stove to boil, conduction heat warms up the pot, which then heats the water molecules inside. As these molecules heat, convection causes them to move away from the interior of the pot as they are replaced by cooler molecules.
Explanation:
I need help with this one
Answer:
B. III and IV
Answer:
b the answer would be b.
The energy available to consumers determined by subtracting the energy used by plants from the total energy
transformed by the process of photosynthesis.
А
et your pas
Primary productivity
B
Gross primary productivity
С
Net primary productivity
D
Cellular respiration
Answer:
C. Net Primary productivity
Explanation:
In an the food chain of an ecosystem, energy is constantly being gained and most. Producers are the set of organisms that start the energy cycle via the process of photosynthesis. The gross primary productivity (GPP) is the amount of energy that the producer is able to capture from sunlight during photosynthesis.
The rate at which that captured energy is used to produce chemical organic compounds, which served as food, is called the primary productivity of the producer. However, the NET PRIMARY PRODUCTIVITY (NPP) is the energy available to consumers, which is determined by subtracting the energy used by plants via metabolism, from the total energy transformed by the process of photosynthesis. Hence, mathematically, NPP = GPP - R
Where, R = energy lost via respiration.
The speed at which waves approach the shore depends on the shoreline features and the depth of the sea floor. When a wave reaches the shore, it releases a burst of energy that generates a current which runs parallel to the shoreline. What is this current called?
Answer:
Longshore current.
Explanation:
A wave is a disturbance which travels through a material medium without any permanent displacement of the particles of the medium. During the propagation of a wave, energy is transmitted from one point to another since waves flow with energy. The higher its speed of propagation, the higher the energy of the wave.
The energy released by the wave at shore produces a current which is referred to as a longshore current.
Answer:
It would be Longshore Current
Explanation:
Hope it helps :)
What is 'b' in this linear equation? y = 5x - 6
A population distribution shows _______.
a.the distribution of age groups within a population
b.the amount of organisms in a unit area
c.the total number of organisms in a population
d.where and in what arrangement organisms are located
Answer:
D
Explanation:
Think about the definition of “distribution “.
What type of bond is being formed in this polymerization reaction to link two amino acids together?
State two features of diffusion that do not apply to active transport
A diagram that shows the connections of many food chains is called a ...
At a depth of 100 meters, what color would a yellow object appear
to a person at that depth?
Answer:
green
Explanation:
PART 2: Test Crosses (Medium difficulty problem)
3. Callie has brown eyes, but her husband Joseph has blue eyes. All three of their children have
brown eyes. Do you know what Callie's genotype is? If yes, what is it? If no, why not?
Help please!!
Answer:
Since Callie has brown eyes, and all her children have brown eyes, we can only assume that the phenotype of brown eyes is dominand and Callie will have a dominant genotype, leaving Joseph to have a reccesive genotype (if Joseph was heterozygous for this aspect, he would have brown eyes) and the children will be heterozygous, with brown eyes as this characteristic predominates over blue eyes.
Information about which of the following would be most pertinent to a small organic farm that solely relies on manual labor to till, plant,
water, and harvest crops?
dehydration and heat exposure precautions
heavy equipment training and maintenance
drip irrigation installation and maintenance
hazardous chemicals storage precautions
Answer:A
Explanation:
If i had to guess its A because its the only one that doesn't require equipment, since the question said it was a small organic farm that only practiced Manuel labor.
Answer:
dehydration and heat exposure precautions
Evan's nightly chores include washing dishes. His mother cooks everything she prepares a bit too long. Because of this, Evan spends a lot of sweat, effort, and time washing dishes. He sees a commercial on television that claims a new dishwashing detergent, called Brand X, cuts through grease better than its competitor, called Brand Y. They back up their claim with testimonials from people who say they've used this new detergent.
What is a possible testable question (in correct format) that Evan might ask for in this scenario?
IV:
DV:
Answer:
product X and Y need to be in a controlled test to make see how they do undergoing the same things.
hope this helps :)
Explanation:
Genetic information is encoded in a linear sequences of nucleotides,
which are structures that contain
A) a sugar group, a phosphate group, and a nitrogen base
B)an amine group, a functional R group, and a carboxyl group
C)short chains of CHO
D)long chains of CHO
Answer:
B)an amine group, a functional R group, and a carboxyl group
Explanation:
can you pls help me ??
Which nitrogenous bases are considered purines?
adenine
cytosine
consider purines
what is property Around a restaurant called
Answer:
I don't understand your question
Compare and contrast a few aspects of animal and plant cells. You can focus on intra- and extracellular structures they share or don't share, but also be sure to describe processes they both utilize or don't both utilize. Some things to consider: How they obtain 'food' (what is their organic carbon source?) What structures do they share that prokaryotes lack? What do they share that all living cells also share? Do they use CO2, and/or O2 in any processes?
Answer and explanation:
Although they share some similarities because they are both eukaryotes, plant cells and animal cells are quite different from each other, which is logical since they have distinct lives.
For example, animal cells and plant cells both have a cell membrane, but only the plant cells have a cell wall - which is thick and resistant, and this makes sense because they are more exposed to mechanical and osmotic stress.
Since animals can move towards sources of water but plants cannot, there's also a way in which plants store water in the cells: vacuoles. Animal cells have vacuoles as well although they are much smaller than the single huge vacuole that plant cells have.
All living organisms need the energy to sustain different cellular processes. The organelle in charge of the chemical reactions behind the obtention of energy is the mitochondria, which is present in all cells, but the mitochondrion needs a specific substrate: glucose. Glucose is obtained in diverse ways: animals move and find food that contains glucose in it, while plants produce their own glucose with a specific process called photosynthesis, for which they need an organelle called chloroplast, which animals do not have. In order to transform the glucose into energy, the mitochondria end up generating CO2, which animals expel from their bodies by exhaling. This CO2, now in the air, is used by plant cells as a substrate in photosynthesis (which needs sunlight as well) to produce glucose and also O2, that will be inhaled by animals and used by their tissues.
All living organisms have one thing in common: they possess DNA. DNA contains all of the genetic information of an organism, and it is present in almost every cell of that organism -if it happens to be a multicellular being-. While prokaryotes have their DNA condensed into a single circular chromosome, eukaryotes like plants and animals, have their DNA form many linear chromosomes (quantity varies according to the species) and these chromosomes are inside a very specialized organelle: the nucleus, which prokaryotes do not have.
I Need Help On Identifying The Characteristics Of Life That Is Illlustarated By Each Of The Following Statements.
The passage of genetic instructions from one generation to the next is known as what?
Answer:
heredity
Explanation:
Answer: heredity because it is
Edxcel alevel biology past papers: some of the blood plasma of individuals who have survived infection wtih Ebola can be collected. This can be used in the treatment of individuals currentlty infected with Ebola. Explain why the blood plasma from survivors can be used to treat new cases of Ebola infection.
Answer:
This was the only treatment options adopted for the Ebola in 1995 in the Democratic Republic of Congo. The assumption was that immune response is generated by the virus in the WBC of the infected individuals. These response produce antibodies.
A total if 8 patients were transfused with these blood contained antibodies, but one of these died, the remaining 7 patients survived.
The antibodies were believed to have multiplied(produced b-cells) to neutralize the Ebola virus(antigens) and to ensure the survival of the patients
Explanation:
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A team of engineers is designing a new ship. The engineers first build several models of the ship. Explain in your own words why the models could help the engineers
Answer:
The model could help the engineers by giving they a prototype to build off of so they have an idea of what they ship looks like, and if the test it, they could troubleshoot and see the errors/successes of the model.
Explanation:
The engineers first build several models of the ship as the model could help the engineers by providing them a prototype to build of so that they have an idea of what or how the ship will looks like, and if they test it, they could troubleshoot and see the errors or successes of the model of the ship.
What are the fields in which science is applied?Science has the factual based knowledge and it has about the Nature as well as the natural world that has created on the basis of observations and the experiments. It has the study of the experiments and observations and it has totally depend upon the scientific result that has obtained after the scientific experiments.
There are several fields in which science has been applied and these field are healthcare, telemarketing, environmental engineering, banking, government regulation, space, biochemistry, physics, chemistry, biochemistry and astronomy, engineering.
Therefore, The engineers first build several models of the ship as the model could help the engineers by providing them a prototype to build of so that they have an idea of what or how the ship will looks like, and if they test it, they could troubleshoot and see the errors or successes of the model of the ship.
Learn more about science here:
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Which one is the correct answer?
Answer: D
Explanation: The moon is about a quarter of the size of the earth
Answer:
at first i was going to say C but now iam sure the answer is D
thermal energy transfer by conduction happens when heat moves from one object to another by
Answer:
Touching
Explanation:
Conduction is when you transfer energy by touching or direct
Answer:
touching
Explanation:
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Answer:
The vaccine that protect humans from the h1n1 virus is called Panvax vaccine or swine Explanation:They are inactivated H1N1 virus vaccines used for immunization of individuals 6 months of age and older against influenza disease caused by H1N1 2009 virus.
Help me plz ..............
Answer: kelvin -tem second- time kilogram- mass meter -length
Explanation:
Two students completed an experiment to determine if pesticide use at local farms was causing fish kills in a local pond. The steps of the experiment are listed below. Select one location to collect water samples in the pond. Collect a 5-mL water sample at 8 am for two days. Measure the amount of pesticide present in each sample using the same measurement tools. After analyzing their data, the students conclude that pesticide runoff from farms is not causing the fish to die in the pond. Which of these statements best describes why their conclusion is not reliable? The pesticide measurements were the dependent variable. The samples were collected at different times. The samples were only collected for two days. The time of sample collection was not an independent variable.
Answer:
The pesticide measurements were the dependent variable
Explanation:
According to this question, an experiment to determine if pesticide used at local farms was causing fish kills in a local pond was conducted by two students. They followed the following steps:
- Select one location to collect water samples in the pond.
- Collect a 5-mL water sample at 8 am for two days.
- Measure the amount of pesticide present in each sample using the same measurement tools
However, after analyzing the data, they concluded that "runoff from farms is not causing the fish to die in the pond". The students' conclusion is not reliable because THE PESTICIDE MEASUREMENTS WERE THE DEPENDENT VARIABLE.
Note that, the dependent variable in an experiment is the measured variable while the independent variable is the manipulated variable. In this case, the students ought to measure the death RATE OF FISH KILLS as the dependent variable instead. The PESTICIDE is the independent variable of the experiment not dependent variable. This was the reason for the unreliability of the conclusion.
how can limiting factors (density dependent and density independent) affect a population size?